m 
[Assembly 
the ore is 5.05, and the foreign matters consisting chiefly of silica 
and alumina, range from eight to fifteen per cent. The masses are 
hard and with difficulty reduced to powder. 
The towns of Hermon and Edwards, in St. Lawrence county, 
contain many interesting and important localities of specular iron. 
Of these, I was supplied with several specimens by Dr. Murdock 
of Gouverneur, and by other gentlemen. They all have a high me- 
tallic lustre, and are often beautifully tarnished; sometimes they 
are composed of laminae or plates and at others they are massive. 
According to Mr. Shepard druses of lenticular or micaceous crys- 
tals, are found at Fowler in the same county.* 
The relative value of the different varieties of this mineral, as of 
those of the magnetic ore, depends in a great measure, upon the 
proportion of foreign matter which they contain. Sometimes, 
indeed, these accompanying substances are of such a nature as to 
injure the quality of the iron obtained, although the ore may be 
sufficiently rich in iron. Thus I observed in one specimen that the 
laminae were separated by a beautiful green mineral, the phos- 
phate of lime, and small masses of quartz were also contained in 
different parts of it. When these were removed, an operation, 
however, attended with some difficulty, I found the remaining por- 
tion to be pure peroxide of iron. 
The presence of phosphate of lime in an ore of iron, is deserv- 
ing of much attention, as the charcoal employed during the process 
of reduction has the effect of decomposing it, at least in part, 
while the liberated phosphorus combines with the iron. If the pro- 
portion of phosphorus be considerable, the iron becomes cold shorty 
or brittle when cold, although at a red heat it is as ductile as iron 
of good quality. It may therefore be used for castings, but is un- 
fit for bar iron. 
While upon this subject it may not be irrelevant to remark, that 
phosphorus so frequently contained in iron ores, and furnished even 
by the ashes of the combustible, does not injure the quality of iron 
unless it exists in a comparatively large proportion. According to 
Karsten, a compound of 10,000 parts of iron and 50 of phospho- 
rus, gives an iron of good quality, which resists the blow of a ham- 
mer. A compound of 10,000 iron and 75 phosphorus, yields an 
* Treatise on Mineralogy, n. 198. 
